1. Field of the Invention
The present invention relates to golf putters. More particularly, the invention relates to an improved golf putter construction which allows both the lie angle and loft angle of a putter to be semi-permanently adjusted or customized by an individual golfer to suit his or her requirements.
2. Description of Background Art
The lie angle of a golf club such as a putter is generally defined as the angle between the ground and the shaft, with the bottom surface or sole of the putter head in flat contact with the ground. This angle is of substantial importance in determining the putting accuracy and success of an individual golfer, for the following reasons.
Preparatory to striking a golf ball resting on a green to propel it towards the cup, a customary and recommended orientation of the golfers body includes facing or addressing the ball along a line perpendicular to a line directed from the ball to the cup, i.e., perpendicular to the direction in which the ball is to be propelled Also, the grip at the upper end of the putter shaft is usually grasped between the hands with the lower end of the shaft angled forward away from the golfer's body, thus positioning the head of the putter behind the ball. Once the putter head is aligned behind the ball with the face of the putter perpendicular to an intended initial roll direction of the ball, the arms are swung rearward to a cocked position, and swung forward to impact and launch the ball. Each individual golfer will, of course, have a preferred stance which feels comfortable to him or her, and will thus tend to address the ball in a more or less stooped orientation of the torso with respect to the legs. Thus, to help insure that the sole of the putter head remains parallel to the ground, putters are customarily provided with shaft lengths which may be selected from a small number of lengths, e.g., 28", 30" and 32", for short, intermediate height and tall golfers, respectively. This shaft length selectability helps to insure that the sole of the putter will be kept parallel to the green surface. However, because of the variation in physical dimensions, as well as stances of golfers, there still remains for many golfers a problem in maintaining the putter sole horizontal. One solution to the problem is to provide a golf putter with a lie angle that is customized by the putter manufacturer to a particular golfer's specifications. However, this approach is less than completely satisfactory for two main reasons. First, the time delay and cost of waiting for a club to be customized is undesirable. Second, many beginning golfers change their stances as they become more experienced, and are therefore not quite sure which lie angle/shaft length combination to choose.
Another mechanical parameter of golf putters which has an important effect on putting performance is the loft angle of the putter. The loft angle is defined as the rearward inclination angle of the club face from the shaft axis. Thus, with a small positive loft angle, e.g., 2-3 degrees, the impact vector, when the ball is struck with the shaft vertically oriented, will have a small, upward component. A small positive loft angle is generally desirable to keep the ball from being inadvertently driven downward into the green surface by the golfer, thus, starting the ball with a bounce, decreasing both its intended roll distance and directional accuracy. However, if the loft angle is too large, the ball will tend to jump off the face of the putter, also decreasing control of distance and path accuracy. Depending upon a given golfer's stance, the true loft angle at the time of ball impact can vary substantially from the static value measured between the club face and shaft. Also, depending upon a particular greens condition, it may be desirable to vary the loft angle. For the reasons set forth above, it would be desirably to provide a golf putter in which the lie angle and/or loft angle may be varied by the golfer to customize the putter for his use and/or to suit differing greens conditions.
In U.S. Pat. No. 5,803,824, Rollingson, a golf putter with lie and offset adapter is disclosed in which the offset, i.e., horizontal spacing between the shaft axis and the bottom end of the front face of the putter, and lie angle are selectively set during factory assembly of the putter, by an adapter. The adapter has an upper elongated portion adapted to fasten to the lower end of a putter shaft and which lies generally in a vertical plane, an intermediate spacer portion which lies generally in a horizontal plane, and a lower elongated portion which is adapted to attach to a putter head or hosel and which lies in a generally vertical plane, the longitudinal axis of which is laterally offset from and angled with respect to the longitudinal axis of the upper portion, at a preselected offset distance and lie angle, respectively.
The present inventor is unaware of any existing golf putters in which the lie angle may be readily adjusted and re-adjusted by an individual golfer, without having to send the club to a pro-shop or manufacturer. Moreover, the present inventor is unaware of any existing golf putter in which the loft angle may be readily adjusted and re-adjusted by an individual golfer. In view of the unavailability of the foregoing features in existing golf putters, the present invention was conceived of.